Why Do We Say: "It's A Doozy"?

Did You Know ...

I was at the Ford Museum in Detroit recently and they had a couple Duesenberg Model J cars from the 1930s on display. As I was standing in awe of these cars, two women were standing next to me talking about how the phrase, "It's a doozy," meaning, something awesome, extraordinary or powerful, comes from Duesenberg's nickname, "Duesy." Duesenbergs were ridiculously expensive in their day, with some costing as much as $25,000 when the average U.S. physician earned less than $3,000 a year.
The women's attribution didn't seem accurate to me, but I was really curious as to the origin so I started poking around online and discovered that no one actually knows for certain where the phrase comes from. But there are some theories.
1) Doozy could be an alteration of an older slang, "It's a daisy," meaning something beautiful.
2) It could have originated around a popular Italian actress during the late 1800s, early 1900s, Eleonora Duse, who often simply went as Duse.
3) According to this video over on Webster, doozy originally appeared as "dozy" in eastern Ohio in 1916 -- four years prior to the production of the first Duesenberg vehicles. They also claim there is little evidence connecting the Duesenberg and doozy during the '20s and '30s, when the car was most popular. "Dozy" is akin to the verb "dozen" that is semantically and etymologically related to "daze."
4) Finally, many people DO, indeed, attribute it the majesty of the Duesenberg car after all, which after doing my research, does seem the most interesting at least, despite what Webster says.